071 Smoke Melts Glaciers and Winter Wildlife Survival Strategies

This week I look at new research that is showing that summer forest fires are having an impact on melting glaciers by literally darkening the ice surface. I also examine the many ways that animals and birds have learned to survive, and in some cases thrive, through very cold winters like this years.

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The Worlds Glaciers are Melting Faster Because of Forest Fire Ash

Over the past few years, I’ve talked a lot about forest fires in western North America and some of the root causes behind them. Fire is a natural part of the ecosystem and attempts by land managers to eradicate it over the past 100 years has led to a complete change in the landscape of this continent. We have three main problems as we look to the future. Each of these will result in more and more fires unless land managers wake up and realize that small fires today can prevent huge conflagrations tomorrow.

These are the challenges that land managers are facing:

1. 1. We have too many trees. Fire prevention has allowed trees to completely fill in landscapes that were previously characterized by meadows connected with stands of trees. Today there are no gaps in the trees, every opening has been filled with wall to wall trees…trees designed to burn.
   2. We have too many people living on the boundary between forests and urban areas. As people encroach on the forests, it puts more and more human lives and property at risk of large scale fires.
   3. Climates are warming and with that, fires are becoming more prevalent.

If you’re a regular listener to this podcast, then this will be nothing new to you. I’ve been hammering these points since the early episodes. If you’d like to learn more about some of the challenges with fire ecology in the mountain west, check out episodes 69, 68, and 41. I’ll leave links to these episodes in the show notes. And by the way, if you’re not a subscriber, be sure to click the subscribe button wherever you consume your podcasts. You can also head to www.MountainNaturePodcast.com and click the big subscribe button so that you don’t miss a single episode.

Some recent studies have shown the impacts of these large fires have far-ranging impacts – and those impacts can be thousands of kilometres away from the fire.

In order to understand those impacts, I need to talk a little bit about positive feedback loops. Unfortunately, when it comes to climate change, there is nothing positive about positive feedback loops.

Snow is white! White snow reflects most of the solar radiation that hits it. This is why large expanses of ice are actually pretty good at staying, well icy. The more ice you have covering a landscape, the more solar radiation is reflected back to the atmosphere.

I’m reminded of a personal experience some years ago. I was buying a new car (the only one I’ve ever owned), and the model I wanted was only available in white. I bit my tongue and signed the contract. I didn’t really think about the colour until the heat of summer arrived. I was amazed at how cool the interior stayed when compared to friends cars that had darker paint jobs. When it comes to heat rejection, white rules.

Unfortunately, as temperatures warm with changing climates, these areas of ice are shrinking. As they shrink, it exposes more and more dark rocks, or in the case of Arctic sea ice, dark water. Rocks and water absorb much more of the solar radiation which allows them to heat up. As they heat up, the rate of melt increases.

This is how we define a positive feedback loop. As more ice melts, more heat is absorbed. Every bit of melt allows additional heat to be absorbed and thus the pace of melt increases. More melt = more heat = more rapid melt.

When I first arrived in the Canadian Rockies way back in 1980, I was amazed at the Columbia Icefields, and in particular, the Athabasca Glacier. As I became a guide, I visited this glacier 40 or 50 times a year, watching it as it slowly began to shrink. By this time, it had been shrinking for 120 years, since the end of the Little Ice Age, but to me, it was a wonder of nature.

Over the past 10 years, I have noticed that the rate of melt has been accelerating. In the past, I marked its shrinking by how far down the valley it extended. Now what stands out is how quickly it is thinning as more and more rock is exposed.

In places like the Canadian Arctic, Iceland, Greenland, and Antarctica, it’s water that is exposed as the ice melts and ice sheets break free. Ocean water is dark and, just like rocks, absorbs much more solar radiation than ice. The more water we expose, the faster the ice melts.

Now there’s a new wrench being tossed into the works – airborne carbon from the same forest fires we’ve spent so much time talking about. On that first trip in 1980, I took a tour onto the Athabasca Glacier. It was a very different and much smaller tour operation than it is today but the experience was the same.

One thing that jumps out at you the first time you walk on a glacier is that they are not actually white. the surface of most glaciers is covered with a combination of dust, pollen, forest fire ash and other airborne particulates that settle on the surface.

That being said, it’s still whiteish, but it’s speckled with flecks of dark particulates. Herein lies the problem. White reflects and dark absorbs. The more of these particulates that cover the surface, the more of the sun’s rays the surface absorbs, and the faster the glaciers disappear.

When we talk about the ability of the Earth’s surface to reflect sunlight, we’re talking about its albedo. The more reflective, or white, a surface is, the cooler it will remain in a particular amount of sunlight. As glaciers become dusted with more and more debris, they simply heat up and their rate of melt accelerates.

Back in episode 51, I referred to a study that took a much more in-depth look at the end of the Pleistocene glaciation.  It found that when glaciers melt, it may take hundreds of years before plants are able to recolonize the landscape. Why does that matter? well scientists tend to use things like carbon dating to date things. Unfortunately, if it takes hundreds or even a thousand years for glacial landscapes to regrow than there isn’t a lot of carbon to date. You can listen to this episode at MountainNaturePodcast.com/ep051

This study found that the glaciers melted much faster than previous studies reflected. Most importantly, it showed that during this period of melting that the glaciers lost as much as half of their mass in less than 400 years. Let me put that into perspective; glaciers that had been there for millennia lost half their mass in just a few centuries!

It also shows just how quickly glaciers can disappear in the right conditions. OK, back to our regularly scheduled program. What might cause glaciers to melt more quickly? Anything that causes them to absorb even a tiny bit more of the sun’s energy. Heat is the enemy of ice, and we’re producing a great deal of it at the moment.

A recent study out of Greenland has found that fires from British Columbia in 2013 were able to show a direct correlation between darkening of the ice surface and the fires that produced the ash.

When particulates enter the atmosphere, they all eventually find their way back to the surface. One of the most important mechanisms is through rain and snow. Every raindrop and snowflake that has ever fallen has had at its core a speck of dust. If this airborne material was not channelled back to the surface, the air would quickly become unbreathable.

Just like water is transformed through the water cycle, particulates are formed, transported, and redeposited as part of the water cycle. With larger and larger forest fires, more and more ash is added to the atmosphere. This ash is light and easily travels thousands of kilometres before being redeposited onto the surface.

A recent study, published in Geophysical Research Letters, was able to quantify the amount of forest fire ash from British Columbia that darkened the surface of glaciers in Greenland in the summer of 2013.

This study, published in 2017 was able to show that one particular smoke plume travelled all the way from parts of Canada including Quebec and British Columbia, to darken the surface of glaciers in Greenland.

So what you might ask. Well, it didn’t darken the surface just a little bit, it darkened it by 57%. This, in turn, means a vast increase in the amount of the suns energy that will be absorbed by the ice surface, and in turn a much faster rate of melting.

When the new millennium first arrived, the rate of winter growth of glacial ice in Greenland was largely balanced by the rate of summer melt. Unfortunately, this equilibrium has shifted so that the glaciers are losing on average around 300 gigatons per year, while 2012 saw some 600 gt vanish in a single season.

Every one of those gigatons represents not a million, but a billion metric tonnes of ice. So how much is that exactly? As soon as you add the word billion, it becomes incomprehensible to most of us. One single gt would be similar to the weight of 100 million African elephants. You need to multiply that by 600 to understand the ice loss of just one year in Greenland as a result of forest fires in Canada. It’s the weight of 60 billion elephants.

Black carbon darkening glaciers is produced by combustion, whether that is through industrial activity or forest fires,

It’s not the simple fact that fires may deposit ash on a glacier that is groundbreaking in this study. It’s the fact that it was able to quantify the amount of ash that a single smoke plume deposited.

It also found that the climate models used to predict so may climatic events, utterly failed when it came to these smoke plumes.

Regardless of what the models predict, Greenland’s glaciers stores vast amounts of water as ice. Were it to melt, it would raise global sea levels by around 7 metres. That would cause an incalculable amount of tragedy across the planet as vast areas found themselves slipping beneath the ocean waves.

It also helped to place fire ash in a much more important context. Prior to this study, ash was seen as an ephemeral impact – much like the clouds that distribute it.

In western Canada, scientists are also beginning to notice the darkening of glacial ice surfaces due to vast amounts of forest fire ash. Glen Pelto has been studying glaciers for years, and recently, on glaciers like the Conrad, south of Golden, B.C. He has also noticed a dramatic darkening of the ice surface during the summer melting season.

On the Alberta side of the divide, Dr. John Pomeroy is also studying these challenges. He has been studying the glaciers of the Canadian Rockies for years and he has seen a marked increase in the amount of solar radiation absorbed on the surface of the mountain glaciers.

Historically, the glaciers absorb approximately 60% of the heat of the sunlight hitting them. More recently they’ve seen absorption rates of 70 or even 80%.

What we’re seeing is a trend. With continuing poor forest management, further complicated by poor prescribed burn plans, the amount of ash being released will likely increase over the next few years.

How Do Animals Survive the Winter?

One of my favourite things to do when I’m taking people out in the winter is to help them to understand the unique ecology that allows an incredible diversity of plants, animals, and birds to survive the cold months of winter.

When we look at a winter landscape, we need to talk about energy losses and how they impact the wildlife and birds that make the mountains home. Energy can be lost through four main mechanisms, radiation, conduction, convection, and evaporation. These represent ways animals lose heat from their bodies, and each species has had to develop strategies to reduce these losses in order to keep their body temperatures from dropping.

Radiation refers to energy being literally radiated from a body. If you put your hand near a sunny window, you can feel the warmer air as the glass radiates away some of that heat. Our bodies also radiate heat, and strategies like fur and feathers are designed specifically to keep heat lost through radiation to a minimum.

If you’ve ever had to handle metal objects like cameras with your bare hands at -30C, you will be very familiar with conduction. The longer we’re in contact with a cold object, the colder we get. Again, feathers and fur are designed to reduce skin contact with snow and thus reduce heat loss through contact.

Wind is another source of heat loss. Convection takes place when cold air moves past an object and takes heat energy with it. This is where wind chill comes into play and it can quickly add up to significant cooling.

Finally, we need to talk about evaporation. When water changes to water vapour, it requires energy. If you build up a good head of steam climbing up a steep trail and start to sweat, that sweat will evaporate and draw heat from your body.

When we breathe on cold days, we lose a lot of heat through evaporation as both energy and water are shed in the process.

How do animals deal with all of these mechanisms of heat loss? Insulation represents an important adaptation. As humans, we put on layers of additional clothing to stay warm. Dead air spaces in the clothing help keep warm air near the body but also reduces the amount of heat lost through conduction.

Fur coats or the feathers of birds have evolved specifically to stop heat from radiating away from the bodies core and reducing the amount of heat lost when laying down on cold snow surfaces.

Different mechanisms can dominate at different times. If you’ve ever gone winter camping, you know how quickly you can lose heat to the ground if you don’t have a good insulating mat beneath you. For animals, conduction can be an important challenge when they bed down for the night.

On the other hand, evaporation may be a more dominant cause of heat loss during activity. Every bird and animal in the mountains needs to find a balance between the amount of food energy available in the winter with the amount of heat they lose to the mountain environment.

Feeding becomes another challenge during winter. Heavy snow packs may make hunting more difficult, reducing the number of calories available for generating heat. At the same time, foods available to some animals in winter may be of much lower quality than during the summer months.

When ecologists talk about adaptations to winter, they often refer to the SCREW factor. This stands for snow, cold, radiation, energy, and wind; and together they are the main factors that shape the evolutionary strategies of animals and birds to allow them to survive in extreme winter conditions.

Each of these factors will impact each species in a different way, resulting in different strategies to adapt. Snow and wind can make accessing food much more challenging. Less food energy can inhibit other processes as well, like reproduction.

While mating may occur at other times of the year, winter is often the time that many animals are pregnant with the next seasons young. If she doesn’t get enough food energy, it may mean that her young don’t survive, or that she doesn’t have enough energy to suckle them when they’re born.

Injuries become much more critical when animals are suffering from insufficient calories as well.

Ecologists group animals into one of three main categories, winter lovers, winter tolerators, and winter avoiders.

Winter avoiders include the hibernators, migrators, and diers. Many local bird species are smart enough to get out of the cold weather before winter sets in. While some birds head south, some, like bald eagles and harlequin ducks do an east-west migration, flying out to the west coast in winter.

Ground squirrels, marmots, and bears avoid winter by retreating into winter dens where they sleep through the cold weather.

Other animals, in particular, some insects, deal with winter by simply dying. Bumblebees are very common during the summer months, but few people realize that every single bee in a colony dies at the end of fall – except one – a newly born queen.

This new queen will mate before winter kills off all the male bumblebees, and then she burrows 20 cm or so into the ground in the hopes of surviving until spring. she then begins the job of starting an entirely new colony – beginning with pollinating flowers like the Calypso Orchid. I talk about how these orchids trick naive bumblebees into visiting (and pollinating) them, even though they don’t offer a nectar reward. You can listen to the show, or check out the show notes at MountainNaturePodcast.com/ep060

Winter tolerators represent the vast majority of mountain animals. Because they don’t have any physiological adaptations to help them survive the winter months, they need to change their behaviour instead.

Mule deer are a good example. Just a small amount of snow accumulation forces mule deer into a bounding gait, which in turn costs a great deal in terms of energy. There comes a time when the energy used for movement outweighs the benefits of that movement.

Instead, mule deer gather in groups and take turns breaking trail. This ‘yarding up’ as it is known, allows them to distribute the energy costs among numerous individuals allowing more of the group to survive the winter. In time, they can pack down the snow to make it easier to move.

And then there are the winter lovers like moose. They’re ice age remnants, literally forged by the cold. They easily walk through chest deep snow almost effortlessly. They also have the ability to lower their metabolism over the course of the winter which, in turn, reduces the amount of energy they need to take in. It’s like turning down the thermostat in your home to save energy.

Their long fur coat has a soft undercoat and longer, hollow guard hairs. These hollow hairs are incredible insulators with their ‘dead air’ space.

Their big bulbous noses are also masterfully engineered. When you and I breathe in winter, we take that cold air directly into our lungs, which can cause a lot of heat loss through evaporation. The long nose of a moose takes the air through a lengthy series of nasal passages that preheats the air before it reaches their lungs.

In fact for moose, this winter has been ideal. They are threatened much more by warming winters as opposed to cold ones. During milder spells, they’ll even lay down in the snow to try to cool down.

Every bird and animal will have a strategy that’s unique to their physiology, feeding habits, and ecological niche.

There are also unique challenges faced by smaller animals. While red squirrels don’t hibernate, they do go into brief periods of inactivity called torpor. I like to think of it as: “it’s -40C out, wake me up in two weeks when it warms up!” I think most of us could relate to that strategy this winter.

Overall, there are only so many strategies available to animals trying to cope with the cold.

The animal’s size plays a big role in determining what options are available to them. Small animals like voles are able to retreat beneath the snows to restrict their movement to tunnels they build to access food sources. Insects like the mountain pine beetle hunker down beneath the bark layers of their namesake pine trees and try to survive until the following spring.

An animals surface to volume ratio also plays a pivotal role in their abilities to withstand the cold. A large animal like a moose has a great capacity to produce heat. In comparison, its surface area is small allowing it to retain more of that heat.

A smaller animal like a pine marten or red squirrel has a much smaller ability to produce heat, and they lose that heat quite quickly to the surrounding environment. This is why it can be very challenging for martens and weasels to stay above the snow for prolonged periods. Instead, they take advantage of the natural hollows produced beneath downed logs. As the snow falls around the log, snow caves are formed which allows them to stay warm under the blanket of snow.

Most people find it had to realize that it never gets cold under the snow. It acts as a blanket and prevents a lot of the cold air temperatures from penetrating beneath its warm blanket.

Another thing you see in some animals is that cold-adapted species will develop shorter ears, snouts, and legs in order to reduce heat loss. That’s why arctic fox are so much smaller than the red fox. It allows them to thrive in much colder habitats than their larger cousins.

Small and medium-sized animals don’t have great fat reserves so their pelts have to be especially warm. Larger animals can rely on fat reserves for some of their warmth at the expense of thick downy coats.

One of the great evolutionary success stories in terms of winter strategies are the snowshoe hares. They have evolved warm pelts to allow them to spend time feeding above the snow and large feet to escape their main prey, the Canada lynx. Unfortunately, in a classic example of co-evolution, lynx have also evolved to have oversize feet to counter the hare’s snowshoes.

Over time, animals adapt to their environments. On the short-term, they need to rely on behaviour to cope with changes. However, given enough time, they can evolve new strategies adapted specifically to their new climatic reality.

Some northern grizzly bears adapted a more streamlined body and white fur to eventually become the polar bears that rule the tundra. As temperatures warm, we will likely see more and more interbreeding between brown and polar bears and we may see a new species emerge.

Genes change with the changes in the world around them. They just need enough time for the process to occur.

This winter, as you head out to hike, snowshoe, cross-country ski or simply explore. Take a look around you and try to spot some of the many ways that animals and birds have found to survive the polar vortex.